WiMAX is a wideband wireless metropolitan area network (WMAN) technology based on the 802.16 series standards of Institute for Electrical and Electronic Engineers (IEEE).
At present, the dual mode mobile phone of global system for mobile communications (GSM)/wireless fidelity (WiFi) based on IEEE 802.1b standard can realize seamless handover between the GSM network and wireless local area network (WLAN), and support unlicensed mobile access (UMA) technology. Users can make up the defect that the indoor signal of mobile terminal such as mobile phone is weak. When network of the mobile phone is busy or the signal is bad, the mobile phone user can perform voice communication through the WiFi network. In practical application, the handover between the two networks is realized through the voice over IP (VoIP) technology, and the expense using this technology is comparatively low and the technology can provide convenience for the mobile phone and wide frequency wireless phone. In addition, the use of the VoIP technology can also realize the functions of browsing web page, sending and receiving e-mail, short messages and multimedia messages and so on. As long as the mobile phone is moved to the areas covered by the wireless wideband, the user can make a free call worldwide by a network phone mode.
In the present network, there are some areas still not covered by the GSM/WiFi networks, or some with bad signals of the GSM/WiFi networks. Aiming at the above-mentioned situations, the mobile phone terminal can realize the communication through the WiMAX network. Therefore, how to realize the intercommunication between the GSM/WiFi dual mode mobile phone and the WiMAX base station is a problem needed to be solved at present.